Support timezone overriding

My Jenkins instance is running in `America/New_York` timezone and it contains one job that needs to be run in `Asia/Shanghai`.

The timeout plugin only allows me to enter time in Deadline strategy and it assumes the time is in Jenkins system timezone. In order to abort its builds at a certain time, I need to change the time twice every year because of the daylight saving switches in New York (since Shanghai does not observe daylight saving at all). Can we make timezone configurable in Deadline strategy so that I don't need to remember to manually change this?

Apologies in advance if this is not a proper place for feature requests. I see the `Issues` tab is open here so didn't think twice. I don't have an Jenkins Jira account.